why can i buy an Ipad cheaper on amazon?

Why? There are many potential reasons for seeing different prices.

Just like other products, Apple does not control pricing offered by Amazon and other third-party retailers - and may differ from Apple's own pricing offered online, or from its retail stores. In some countries, retail price control by a manufacturer is illegal.

When shopping at the Amazon website, be aware that not all products are being sold on the website by Amazon itself - but might instead be from an independent reseller via Amazon Marketplace. Amazon and other retailers often have "offer" prices - in particular at certain times of the year (e.g., Black Friday sales). Don't forget, refurbished devices that are sold through many retailers are not "new" - and pricing may reflect this difference.

When considering purchase of a new device, consider that buying directly from Apple has some advantages. While you will always pay Apple's list-price, in most countries/regions you benefit from Apple's own 14-day returns policy - where you can unconditionally return an undamaged item for full refund or exchange, whether it device has been used or not. As such, if an Apple product is unsuitable - or you would prefer a different model - you can try the item at home without risk. Other retailers are unlikely to have such a generous returns policy.

My daughter bought me an Apple TV box at WalMart because it was cheaper than at Apple. Guess what? It turned out to be a "recently discontinued" model.

I see too many posts of regret here about buying from non-Apple source that end in tears. Do as you wish, but after over 20 years of seeing sad tales here, I buy only Apple-direct with zero regrets. To heck with saving a few bucks!

As the Romans said, cavaet emptor!